1. Field of the Invention
The present invention relates to a welded construction and to a method of resistance welding.
2. Description of the Related Art
Resistance welding is per se known as a method of locally welding together two metallic members. Resistance welding is a method of welding by flowing an electrical current through portions where the members are to be welded together and thus generating Joule heat, while at the same time pressing the members together.
In order to locally concentrate the electrical current that flows in the members to the portions to be welded, the contact area is made to be small for achieving higher electrical current density. Due to this, a portion projecting point-wise or line-wise is normally provided on one of the metallic members to be welded, so that point contact or line contact thereof can be established with the other metallic member.
In this case, during resistance welding, with the metallic members that are to be welded together being contacted together at the projecting portion, positive and negative welding electrodes are respectively pressed against the surfaces of the two metallic members opposite to their surfaces that are to be welded together.
There is a method of construction in which, when forming the projecting portion upon the metallic member, the portion of the metallic member where the projecting portion is formed is made thicker than the surrounding region. However, with this construction, the efficiency of material utilization is poor.
Thus, a method is known of using a plate shaped metallic member, and of forming the projecting portion by pressing (for example, refer to Japanese Laid-Open Patent Publication 2006-032072). By doing this, it is possible to enhance the efficiency of material utilization, thus reducing the cost.